1. Field
The present invention generally relates to a power grid frequency flexible operation system and method using the same, and particularly, to a system and method for flexibly controlling a frequency range of electrical power supplied according to consumer characteristics.
2. Description of Related Art
To supply electricity to individual consumers, electricity generated at a power station or other electricity supplying facility is transmitted via a power grid. A power grid denotes an entire process for electricity from generation to end use. All nationally or regionally interconnected and operated power stations are connected with transmission lines, substations, distribution lines, and consumers, and 765 kV, 345 kV, 154 kV, and 66 kV flow in transmission lines, and at substations, 765 kV is converted to 345 kV, which is converted to 154 kV, which is then converted to 22.9 kV. A power grid is controlled to maintain a balance in power generation, distribution, and use. That is, operational conditions of power stations, such as electric power generator output, electric power flow in transmission lines, frequency and system voltage vary according to constantly changing demand. Also, unstable factor always exists in power grids due to external factors, such as a storm or stroke of lightning, and internal factors, such as power-grid system failure and other physical phenomenon.
On the domestic side, electricity provided to all loads in a current power grid has a frequency range of 60 Hz±0.2 Hz. Such high quality electricity is provided to all loads; however, high-quality electricity need not necessarily be supplied to all loads or, in other words, consumers. Especially, high economic cost is expended in providing high-quality electricity. Moreover, as frequencies in domestic power grids are uniformly synchronized throughout the power grids, it is impossible to supply in the form of existing power grids, frequency/frequencies of different quality within a given power grid.